The present invention relates generally to electron microscopy for imaging samples, and more specifically to apparatus and methods for imaging crystalline structures.
Since electron microscopes generally utilize the small de Broglie wavelength of electrons, electron microscopes can image at significantly higher resolutions than light microscopes. One application of electron microscopy enables examination of relatively tiny structures of a specimen, such as a single column of atoms or the crystalline structure of a material.
An operator of an electron microscope may encounter several challenges when attempting to image a crystalline structure at high resolutions, e.g., so as to resolve individual atoms. For example, unless the atoms of such a crystalline structure are perfectly aligned relative to the viewing axis so that the atoms in each column that is parallel to such axis are aligned, any misaligned atoms will tend to blur together so that the individual atoms cannot be precisely imaged with clarity. The operator typically repeatedly, manually tilts the sample until the atomic columns are perfectly aligned in a particular polar orientation. Additionally, once the sample is tilted precisely so as to image at a first polar orientation, the operator will often need to again repeatedly tilt the sample so as to image the sample at a different polar orientation. The operator typically manually performs numerous and time consuming tilt adjustments at each different polar orientation so as to achieve a clear image at such different polar orientations.
The efficiency of such manual alignment techniques is highly dependent on the particular expertise of the operator and, additionally, these manual alignment processes tend to be very tedious for the operator. Accordingly, improved mechanisms and techniques for facilitating the imaging of crystalline structures would be beneficial.